In India it is considered bad luck to receive a present wrapped in black and white, ruling out the possibility of some cheapskate using newspaper.
Argentinians tug on the earlobes of the birthday boy or girl, one pull for each year; the older you get, the longer you have to endure this potential awkwardness.
People in Bulgaria (as well as several other countries) fortunate enough to have a historic or biblical name get two birthdays! - one on the actual day and then a much bigger one on their 'name day'.
In China and Japan it is considered that everyone grows a year older on New Year,regardless of the actual date they were born.
Many Russians do not receive birthday cakes but birthday pies. Nuff said. Apparently it is also customary if you are still at school for your teacher to give you a present!
Somewhat depressingly Koreans hold a small celebration 100 days after a child is born to celebrate their having survived this far. But the first proper birthday is also an important affair, and often the child's fortune is told (by surrounding them with objects and seeing which ones they pick up).
In Denmark a flag is flown outside the house to indicate someone inside is having a birthday.
In Mexico - this.
In Lewis Carroll's world the concept of an un-birthday exists, allowing for 366 days of pure celebration.
And Wikipedia introduces the birthday paradox and birthday attack, which on clicking turn out to be two of the biggest letdowns ever.
I'm gonna go be 19 now.
